SOD (GliSODin).

SOD converts superoxide into hydrogen peroxide, which is itself reactive. Catalase decomposes that peroxide to water and oxygen, so the pair completes one clearance step end to end.

Glutathione peroxidase consumes reduced glutathione to remove the hydrogen peroxide SOD produces. Glutathione supply sets how quickly the second half of the pathway runs.

Glutathione peroxidase is a selenoenzyme, so selenium status governs peroxide clearance downstream of SOD. Low selenium makes that step the bottleneck.

Cu/Zn-SOD carries copper at its catalytic centre and copper performs the electron transfer. Copper status is one determinant of endogenous SOD activity.

Zinc holds the structural site of Cu/Zn-SOD and stabilises the geometry around the copper. The enzyme folds correctly only with it in place.

MnSOD, the mitochondrial isoform, carries manganese at its active site. Manganese supply supports the isoform nearest to where superoxide arises during normal respiration.

Ascorbate covers aqueous radical species that a superoxide-specific enzyme does not act on, and it regenerates oxidised tocopherol. The two sit at different points of the same network.

Alpha-tocopherol interrupts lipid peroxidation chains inside membranes while SOD works in aqueous compartments. Together they cover both phases.

Lipoic acid regenerates ascorbate and glutathione, the carriers that finish what SOD starts, and it moves through both water and lipid compartments.

NAC delivers cysteine, the limiting amino acid for glutathione synthesis. Glutathione is what the downstream peroxidase needs to clear SOD-derived peroxide.

Free ferrous iron reacts with hydrogen peroxide through Fenton chemistry to form hydroxyl radicals. Raising dismutation without matching peroxide clearance in the presence of loose iron relocates the chemistry instead of ending it.

A dedicated transporter concentrates ergothioneine in mitochondria, where MnSOD operates. It buffers thiol oxidation in that same compartment.

Vitamin B12 was given together with superoxide dismutase, alpha-lipoic acid and carnitine in a randomised study of adults with high blood sugar and nerve-related symptoms. Because the four were tested as one product, the trial supports the combination and not any single component. B12 has its own established role as a cofactor in methylmalonyl-CoA and methionine synthase reactions in nerve tissue.

Carnitine was one of the four components in the same randomised combination study. Its own established role is shuttling long-chain fatty acids into the mitochondrion for oxidation, which sits upstream of the mitochondrial superoxide that SOD handles. The trial tested the fixed combination, so it cannot separate carnitine's contribution.

Sulforaphane activates Nrf2, the transcription factor that drives expression of the body's own antioxidant enzymes including superoxide dismutase, catalase and glutathione-linked enzymes. That is a different route from swallowing the enzyme itself: one raises endogenous production, the other supplies exogenous protein. The Nrf2 relationship is settled molecular biology; the size of any enzyme increase from a supplement dose in people is a separate question.

Broccoli sprout extract is the usual delivery route for glucoraphanin, which myrosinase converts to sulforaphane, the Nrf2 activator. It therefore reaches the same endogenous antioxidant enzyme response by a food route. Conversion depends on plant or gut myrosinase activity, so delivered sulforaphane varies between products.

Coenzyme Q10 carries electrons between complexes I and III of the respiratory chain, and it is leakage at those same complexes that generates the superoxide manganese-SOD deals with inside the mitochondrion. The two sit on either side of the same event: one supports electron flow, the other clears what escapes. This is settled bioenergetics rather than a measured combination effect.

Astaxanthin is a lipid-phase carotenoid that quenches singlet oxygen and interrupts lipid peroxidation chains inside membranes, whereas superoxide dismutase works on superoxide in the aqueous phase. They act in different compartments on different species. The pairing is chemically complementary; no trial has measured the two together.

Quercetin scavenges radicals directly and chelates transition metals that would otherwise catalyse hydroxyl radical formation from hydrogen peroxide. Since hydrogen peroxide is the product of the SOD reaction, metal chelation sits immediately downstream. The mechanism is well described in vitro; human combination data does not exist.

Proanthocyanidins from grape seed act as chain-breaking antioxidants in the aqueous and membrane interface. They are frequently formulated alongside enzyme-based antioxidant ingredients. The pairing rests on complementary chemistry rather than measurement.

Pine bark proanthocyanidins scavenge radicals and are reported to spare other antioxidants in vitro. That places them in the same recycling network as ascorbate and tocopherol rather than in competition with an enzyme. There is no combination trial with SOD preparations.

Curcuminoids activate Nrf2 and dampen NF-kB signalling in preclinical models, which raises expression of endogenous antioxidant enzymes. That is an indirect route to the same enzymes an oral SOD product supplies directly. Curcuminoid bioavailability is the limiting step and is why formulation matters more here than dose on the label.

Resveratrol raises manganese-SOD expression through sirtuin and FOXO signalling in cell and animal work. Human data on enzyme expression at supplement doses is thin. Read this as a preclinical mechanism, not an established human effect.

Pterostilbene is a dimethylated stilbene closely related to resveratrol with greater metabolic stability, and it acts on the same Nrf2 and sirtuin signalling in preclinical models. The comparison to resveratrol is pharmacokinetic, not a claim of greater effect. No human combination work exists.

Riboflavin becomes FAD, the cofactor glutathione reductase needs to regenerate reduced glutathione. Glutathione peroxidase then disposes of the hydrogen peroxide that the SOD reaction produces. Without functioning downstream disposal, dismutating superoxide simply moves the load one step along.

Cysteine is the rate-limiting amino acid for glutathione synthesis, and glutathione is what peroxidase uses to clear the hydrogen peroxide left by the SOD reaction. Supplying the precursor keeps the downstream arm of the pathway running. This is standard sulfur amino acid biochemistry.

Glutathione is a tripeptide of glutamate, cysteine and glycine, so glycine is one of its three building blocks. It is rarely limiting in the way cysteine is, but it is a required input. Its relevance here is entirely through the hydrogen peroxide disposal step downstream of SOD.

EGCG is a strong direct radical scavenger and metal chelator in vitro and also engages Nrf2 signalling. Both routes touch the same antioxidant network as an SOD product without competing with it. Note that catechins can also behave as pro-oxidants at high concentrations in vitro, which is part of why dose matters.

Lycopene is a lipid-soluble carotenoid that works inside membranes and lipoproteins, quenching singlet oxygen. It needs dietary fat for absorption. Its compartment is different from the enzyme's, which is why the two are described as complementary rather than overlapping.

Tocotrienols are vitamin E family members that terminate lipid peroxidation chains in membranes and are recycled by ascorbate at the membrane surface. The recycling network sits alongside the enzymatic arm rather than inside it. No trial has combined them with an SOD preparation.

Xanthine oxidase is a molybdenum-dependent enzyme and one of the notable cellular sources of superoxide during purine breakdown. Molybdenum status therefore sits upstream of the substrate SOD acts on. The relationship is real biochemistry and works in the opposite direction from a typical additive pairing, so it is flagged as modulating rather than additive.